(a) Technical Field of the Invention
The present invention relates the field of target tracking and more generally to a method employing multiple model and variable sampling rate technique, which achieve good tracking performance for the high-g maneuvering missile targets.
(b) Description of the Prior Art
For tactical situation awareness and threat assessment in modern battlefield, target tracking is one of the most important areas of concern, especially in missile tracking (eg. Air-to-Air (A/A), Air-to-Ground (A/G), etc.). Missile maneuvers have high g which can range up to 50 g (e.g. Missile loaded by Eurofighter Typhoon) and are extremely unpredictable. The conventional Kalman filter is widely used as a target tracking technique, however it is not capable of handling such high-g maneuvering targets and may cause track loss during high-g missile maneuvering.
The use of the Interacting multiple Model (IMM) algorithm and the Interacting Acceleration (IAC) algorithm in target tracking gives better performance than the Kalman filter. This has been disclosed in xe2x80x9cINTERACTING MULTIPLE MODEL METHODS IN TARGET TRACKING: A SURVEYxe2x80x9d, IEEE Transactions on Aerospace and Electronic Systems, Vol. 34, No. 1 January 1998, by E. Mazor, A. Averbuch, Y. Bar-Shalom and J. Dayan, and xe2x80x9cINTERACTING ACCELERATION COMPENSATION ALGORITHM FOR TRACKING MANEUVERING TARGETSxe2x80x9d, IEEE Transactions on Aerospace and Electronic Systems, Vol. 31, No. 2 July 1995, by G. Watson and W. Blair. These multiple model methods have attracted increasing applications in Air Traffic Control (ATC), Missile Launch Envelop (MLE) and Dynamic Launch Zone (DLZ) systems in the recent years.
In the applicant""s previous patent (Singapore application number 200102213-6), the Interacting Multiple Model (IMM) and the Interacting Acceleration Compensation (IAC) algorithms for maneuvering targets have been modified to achieve significantly better tracking performances. In the present invention, by combining the variable sampling rate method with the Modified Interacting Multiple Model (MIMM) and the Modified Interacting Acceleration Compensation (MIAC) algorithms respectively, the tracking performance of the MIMM and MIAC for high-g maneuvering targets, especially for the A/A and A/G missile targets tracking, will be further improved.
Accordingly, it is an object of the present invention to provide a high-g, maneuvering missile tracking method by combining the variable sampling rate method with the MIMM algorithm to formulate the VMIMM tracking algorithm, wherein the variable sampling rates are introduced according to target maneuvering detection which is related to adaptive factor, "xgr".
Also, another object of the present invention is to provide a high-g maneuvering missile tracking method by combining the variable sampling rate method with the MIAC algorithm to formulate the VMIAC tracking algorithm, wherein variable sampling rates are introduced according to target maneuvering detection which is related to adaptive factor, xcex6.
A further object of the present invention is to provide a maneuvering missile tracking method by combining the variable sampling rate method with the MIMM and the MIAC algorithms respectively, wherein simulation results show that the modified algorithms perform better than the original algorithms.